fpcmake is used to regenerate the MakeFiles. I'm sure this is not what you want to do, since the MakeFiles in the source distribution should be up to date already (except in rare instances when the development branch could be in an inconsistent state).
Can you compile a simple hello world program with FPC? What is the output of the following:
$ echo "program hello; begin writeln('hello'); end." > hello.pp
$fpc -va hello.pp
If you get an error that fpc is not found, you should specify the full path to fpc:
$ /path/to/fpc -va hello.pp
If there is a problem with the compiler setup this should list the problem.
Then go back to the lazarus source folder and run
make again. If fpc is not found in the path, remember to add FPC=/path/to/fpc to the make command.